Answer:
r=(A/π)^1/2
Step-by-step explanation:
A=πr^2. When dividing π on both sides, you get r^2 = A/π. Meaning that r = the square root of A/π, or (A/π)^1/2
1. In a week there are 7 days. So your andwer would be 21/10. The decimal is 2.1.
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